US9447879B2 - Piston ring - Google Patents

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US9447879B2
US9447879B2 US14/650,115 US201314650115A US9447879B2 US 9447879 B2 US9447879 B2 US 9447879B2 US 201314650115 A US201314650115 A US 201314650115A US 9447879 B2 US9447879 B2 US 9447879B2
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coating
crn
tin
thickness
piston ring
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US20150308573A1 (en
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Masayuki Sato
Yuuichi Murayama
Youhei IWAMOTO
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Riken Corp
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Riken Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/26—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction characterised by the use of particular materials
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/0641—Nitrides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/24—Vacuum evaporation
    • C23C14/32—Vacuum evaporation by explosion; by evaporation and subsequent ionisation of the vapours, e.g. ion-plating
    • C23C14/325—Electric arc evaporation
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C23C28/042—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C23C28/044—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material coatings specially adapted for cutting tools or wear applications
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/40—Coatings including alternating layers following a pattern, a periodic or defined repetition
    • C23C28/42—Coatings including alternating layers following a pattern, a periodic or defined repetition characterized by the composition of the alternating layers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F5/00—Piston rings, e.g. associated with piston crown

Definitions

  • the present invention relates to a piston ring for automobile engines, particularly to a piston ring having hard laminate coating formed by ion plating for excellent scuffing resistance, wear resistance and peeling resistance.
  • Piston rings have recently become used in increasingly severer environment, due to higher power of engines, higher combustion temperatures and larger load for meeting exhaust gas regulations, the use of low-viscosity lubricating oils, the diversification of fuels such as bioethanol, higher fuel injection pressure, etc.
  • Even piston rings having hard chromium nitride (CrN) coatings formed by ion plating, which are now considered as having best scuffing resistance and wear resistance, may fail to exhibit sufficient performance due to the peeling of coatings by cracking and chipping. Accordingly, improvement in scuffing resistance, wear resistance and peeling resistance has been more strongly demanded than even.
  • Patent Reference 1 discloses a coating obtained by alternately laminating a columnar layer of CrN crystals oriented in a direction from a substrate surface to a coating surface, and a flat layer, or a coating obtained by alternately laminating a layer having porosity of 0-0.5% by volume and a layer having porosity of 1.5-20% by volume, to prevent the peeling of the coating due to chipping caused by chipping fatigue on an outer peripheral surface.
  • Patent Reference 2 discloses a thick, hard coating with reduced internal stress and high adhesion, which alternately comprises hard composite nitride layers of columnar crystals (for example, CrSiN and TiSiN), and non-columnar crystal layers relaxing the stress of the hard composite nitride layers, by alternately repeating high bias voltage conditions for forming columnar crystals and low bias voltage conditions for forming non-columnar crystals with constant intervals.
  • hard composite nitride layers of columnar crystals for example, CrSiN and TiSiN
  • non-columnar crystal layers relaxing the stress of the hard composite nitride layers
  • Patent References 1 and 2 disclose laminate coatings of nitrides having different structures (columnar structure and non-columnar structure, or porous structure and dense structure), and Patent Reference 3 discloses a different-composition laminate coating comprising metal layers as the stress-relaxing layers in Patent Reference 2. Though the metal layers relax stress more than the composite nitride layers of Patent Reference 2, they have an adverse effect on scuffing resistance.
  • Patent Reference 4 discloses a piston ring having a laminate coating formed by alternately laminating compound layers of titanium, carbon and nitrogen, and compound layers of chromium, carbon and nitrogen. To form a coating exhibiting excellent wear resistance without chipping when used for top rings of diesel engines, Patent Reference 4 determines the amount of carbon dissolved in a solid solution and porosity, such that the hard coating has fracture toughness of about 3 MPa ⁇ m 1/2 or more, and hardness Hv of 1700 or more.
  • An object of the present invention is to provide a piston ring having a hard laminate coating formed by ion plating for excellent scuffing resistance, wear resistance and peeling resistance, which can be used in an environment under high mechanical and thermal load in engines.
  • the inventors have investigated the influence of fracture toughness, hardness and residual stress, as well as the properties of materials constituting the coating, such as Young's modulus and thermal conductivity, etc. on mechanical stress and thermal stress applied to a hard coating formed on a piston ring by ion plating.
  • the inventors have found that by laminating a compound having high Young's modulus and thermal conductivity and a compound such as chromium nitride introducing relatively low residual stress, with the thickness of each layer close to each crystallite size, it is possible to provide a piston ring with a hard laminate coating having improved hardness and thermal conductivity, the optimized residual stress, as well as excellent scuffing resistance, wear resistance and peeling resistance.
  • the piston ring of the present invention has a hard coating as thick as 10-60 ⁇ m on an outer peripheral sliding surface thereof,
  • the hard coating being formed by alternately laminating two types or more of layers made of different compounds
  • each of the compound layers being made of a nitride of at least one metal selected from the group consisting of Ti, Cr, Zr, V, Hf and Al.
  • the compound layers In order that the compound layers have high thermal conductivity, rigidity and strength, they preferably have as high crystallinity as possible.
  • the thickness of a unit laminate which is a sum of the thickness of each different-type layer in the laminated compound layers, is preferably 20-100 nm, and 1-3 times a sum of the crystallite size of each compound layer.
  • the compound layers are preferably made of CrN-type chromium nitride and TiN-type titanium nitride.
  • the hard coating preferably has hardness Hv of 1150 or more, and residual compression stress of 1500 MPa or less.
  • the thickness of a unit laminate is more preferably 1-1.3 times a sum of the crystallite size of each compound layer.
  • a ratio of titanium is preferably high for thermal conductivity, and a ratio of chromium is preferably high for corrosion resistance.
  • the atomic ratio of chromium to titanium is preferably in a range of 3/7 to 7/3.
  • a surface of the hard coating preferably has the maximum X-ray diffraction intensity in a (200) plane of CrN in the chromium nitride layer, and in a (200) plane of TiN in the titanium nitride layer.
  • FIG. 1 is a schematic view showing an arc ion plating apparatus used in the present invention.
  • FIG. 2 is a scanning electron photomicrograph showing a cross section of the piston ring of Example 1 having a CrN/TiN laminate coating.
  • FIG. 3 is a view showing an X-ray diffraction pattern in Example 1.
  • FIG. 4 is a schematic view showing a rolling contact fatigue test machine.
  • the piston ring of the present invention is provided with a hard coating as thick as 10-60 ⁇ m on an outer peripheral sliding surface thereof, the hard coating being formed by alternately laminating two types or more of layers made of different compounds, and each of the compound layers being made of nitride of at least one metal selected from the group consisting of Ti, Cr, Zr, V, Hf and Al.
  • Nitrides may be TiN, CrN, ZrN, VN, HfN, AlN, TiAlN, etc.
  • the laminate coating is preferably CrN/TiN, CrN/AlN, TiN/AlN, TiN/ZrN, CrN/ZrN, CrN/TiAlN, etc.
  • Non-Patent Reference 1 CrN and TiN formed by arc ion plating have thermal conductivities of 0.0261-0.0307 cal/cm ⁇ sec ⁇ deg (10.9-12.9 W/m ⁇ K in an SI unit) and 0.07 cal/cm ⁇ sec ⁇ deg (29.3 W/m ⁇ K in an SI unit), respectively, the thermal conductivity of TiN being about 2.5 times as high as that of CrN.
  • they have Young's moduli of 430 GPa and 550 GPa, respectively, the Young's modulus of TiN being about 1.3 times as high as that of CrN.
  • a CrN/TiN laminate coating has higher thermal conductivity and Young's modulus than those of a CrN coating.
  • CrN-type chromium nitride means that the chromium nitride is mainly a CrN type, though it may contain Cr 2 N-type chromium nitride.
  • TiN-type titanium nitride means that the titanium nitride is mainly a TiN type, though it may contain Ti 2 N-type titanium nitride.
  • the hard laminate coating of the present invention has higher thermal conductivity than that of the conventional hard CrN coating.
  • the thickness of a unit laminate is a sum of the thickness of each different-type layer in the laminated compound layers.
  • a CrN/TiN laminate coating for example, it is a sum of the thickness of one CrN layer and the thickness of one TiN layer.
  • the thickness of a unit laminate is preferably 20-100 nm. When the thickness of a unit laminate is less than 20 nm, a growing speed of the coating should be low, resulting in undesirably low productivity in forming a hard coating as thick as 10-60 ⁇ m, particularly more than 40 ⁇ m, on the piston ring of the present invention.
  • the thickness of a unit laminate is more than 100 nm, crystal grain boundaries and defects such as pores likely increase due to a high growing speed of the coating. Accordingly, the thickness of a unit laminate is preferably 100 nm or less. From the aspect of the propagation of cracking, the thickness of a unit laminate is preferably 20-80 nm, more preferably 20-60 nm.
  • the hardness Hv of the coating is preferably 1150 or more.
  • the coating has hardness Hv of less than 1150, cracking undesirably occurs vertically to the coating surface.
  • the hardness Hv is preferably 1450 or less.
  • the coating When the residual stress of the CrN/TiN laminate coating exceeds 1500 MPa as compression stress, the coating is more easily peeled. Accordingly, the residual stress is preferably 1500 MPa or less. Because lower residual compression stress provides the coating with lower hardness, the coating preferably has residual compression stress of at least 300 MPa.
  • the CrN/TiN laminate coating may be regarded as a single crystal at least in a thickness direction, exhibiting much higher rigidity than polycrystals.
  • the coating may be considered as being composed of polycrystals having boundaries with small inclination to the coating surface. This structure suppresses the propagation of cracking on and in the laminate coating.
  • the thickness of a unit laminate composed of a CrN layer and a TiN layer is preferably 20-100 nm, and in a range of 1-1.3 times a sum of the crystallite sizes of CrN and TiN.
  • the thickness of a unit laminate is preferably 20-100 nm, and in a range of 1-1.3 times a sum of the crystallite sizes of CrN and TiN, from the aspect of strength and thermal conductivity.
  • the solid solution of a third element (carbon) as described in Reference 4 is undesirable, because of thermal conductivity reduced by phonon scattering.
  • TiN has thermal conductivity about 2.5 times as high as that of CrN as described above, the lamination of TiN increases the thermal conductivity of the entire coating.
  • TiN is poorer in corrosion resistance than CrN. Accordingly, the ratio of titanium is preferably high for thermal conductivity, and the ratio of chromium is preferably high for corrosion resistance. From the aspect of their balance, it is further preferably in a range of 3/7 to 7/3.
  • the growth directions of the CrN layer and the TiN layer to be laminated are different depending on the film-forming conditions.
  • the CrN layer preferably has the maximum diffraction intensity in a (200) plane
  • the TiN layer preferably has the maximum diffraction intensity in a (200) plane.
  • a metal layer may be formed between the laminate coating and the substrate to improve their adhesion.
  • the CrN/TiN laminate coating is formed by an arc ion plating apparatus schematically shown in the plan view of FIG. 1 .
  • This arc ion plating apparatus comprises a vacuum chamber 1 having a gas inlet 2 and a gas outlet 3 , a rotary table 6 on which articles 7 (stacked piston rings) are placed, and a metallic Cr cathode (target) 4 and a metallic Ti cathode (target) 5 arranged as evaporation sources at opposing positions via the rotary table 6 .
  • the articles 7 per se are rotated on the rotary table 6 .
  • the evaporation sources 4 , 5 are connected to anodes (not shown) of an arc power supply, and the rotary table 6 is connected to a bias power supply (not shown).
  • a heater 8 is arranged on a wall of the apparatus.
  • arc is generated on the metallic Cr cathode and/or the metallic Ti cathode as evaporation sources to instantaneously melt metallic Cr and/or Ti, thereby ionizing them in a nitrogen plasma; and chromium ions, titanium ions, or CrN or TiN formed by reaction with nitrogen plasma are attracted to the articles 7 to which negative bias voltage is applied, thereby forming thin films.
  • the CrN/TiN laminate coating may be obtained by alternately forming CrN and TiN by alternate discharge of the metallic Cr cathode and the metallic Ti cathode, the discharge of the metallic Cr cathode and the discharge of the metallic Ti cathode are carried out preferably simultaneously to increase the film-forming speed and thus productivity. Because the amounts of Cr and Ti evaporated from the metallic Cr cathode and the metallic Ti cathode and a partial pressure of a nitrogen gas determine the compositions of chromium nitride and titanium nitride, they are adjusted in the present invention, such that the resultant coating is based on CrN-type chromium nitride and TiN-type titanium nitride.
  • the ratio of Cr to Ti can be adjusted by changing arc current within such a range as not to change the composition (for example, from a CrN-based composition to a Cr 2 N-based composition).
  • the thickness of each CrN layer and each TiN layer can be controlled by arc current and the rotation speed of the rotary table 6 .
  • the thickness of the CrN layer and the TiN layer can be directly measured by a field emission scanning electron microscope (FE-SEM), etc., and the thickness of a unit laminate of one CrN layer and one TiN layer, which is formed during one rotation of the rotary table, is a value obtained by dividing the film-forming speed ( ⁇ m/min) by the rotation speed (rpm) of the table. Because a higher film-forming speed is obtained by higher arc current, higher arc current or a higher rotation speed of the table provides a unit laminate with smaller thickness.
  • FE-SEM field emission scanning electron microscope
  • the crystal structure of the coating formed by arc ion plating can be controlled by pressure in the furnace and bias voltage.
  • High pressure in the furnace and low bias voltage provide columnar crystals
  • low pressure in the furnace and high bias voltage provide granular structure.
  • Patent Reference 2 teaches that high bias voltage provides columnar crystals.
  • a film-forming ion plating environment is extremely complicated. For example, the same structure would not necessarily be obtained with the same arc current, furnace pressure and bias voltage, if the apparatus were changed.
  • the arrangements of articles, evaporation sources, etc. in the furnace have relatively large influence on the structure, in addition to substrate materials, crystal structures, temperatures, surface conditions, etc.
  • the film-forming conditions should be set depending on the apparatus.
  • Piston rings each having a rectangular cross section and a barrel-faced outer peripheral surface [nominal diameter (d): 96 mm, thickness (al): 3.8 mm, and width (h1): 2.5 mm] were formed from a wire of SWOSC-V, and 50 piston rings were stacked, shot-blasted on their outer peripheral surfaces to surface roughness (Ry) of several ⁇ m, and set in an arc ion plating apparatus (AIP-S40 available from Kobe Steel, Ltd.), which had a target of 99.9-%-pure metallic chromium and a target of 99.9-%-pure metallic titanium.
  • AIP-S40 available from Kobe Steel, Ltd.
  • the thickness of a coating was determined by measuring the distance from the coating surface to the substrate surface on a scanning electron photomicrograph (SEM photograph) of a cross section of a mirror-polished piston ring perpendicular to the coating surface.
  • FIG. 2 shows a SEM photograph.
  • the thickness of the coating was 29.1 ⁇ m in Example 1.
  • the dark gray coating slightly contained metallic Cr droplets (bright white).
  • the thickness of a unit laminate (a chromium nitride layer+a titanium nitride layer) formed during one rotation of the rotary table was calculated as 0.0364 ⁇ m (36.4 nm), from the above thickness of 29.1 ⁇ m, the coating time of 400 minutes, and the number of table rotation of 2 rpm.
  • Example 1 Using a micro-Vickers hardness meter, the hardness of a mirror-polished coating surface was measured at a test force of 0.9807 N.
  • the CrN/TiN laminate coating of Example 1 had hardness Hv of 1290.
  • the residual stress in Example 1 was ⁇ 843 MPa (843 MPa as a compression stress).
  • the X-ray diffraction intensity of a mirror-polished coating surface was measured in a 20 range of 35-70°, using Cu-K ⁇ rays at a tube voltage of 40 kV and a tube current of 30 mA.
  • the X-ray diffraction pattern of Example 1 exhibited diffraction peak intensities, which was maximum in a (200) plane of TiN, followed by a (200) plane of CrN and a (111) plane of TiN.
  • the crystallite sizes D hkl in a (200) plane of TiN and a (200) plane of CrN were calculated by the following Scherrer equation.
  • D hkl K ⁇ / ⁇ cos ⁇ (2), wherein K is a Scherrer constant of 0.94, ⁇ is a wavelength of X rays (Cu: 1.5406 ⁇ ), ⁇ is a full width at half maximum (FWHM), and ⁇ is a Bragg angle.
  • the CrN layer had a crystallite size of 9.0 nm
  • the TiN layer had a crystallite size of 22.9 nm, so that a sum of the crystallite sizes of a CrN layer and a TiN layer was 31.9 nm.
  • the thickness of a unit laminate calculated from the coating thickness was 36.4 nm, 1.14 times a sum of the crystallite sizes of chromium nitride and titanium nitride.
  • the composition of the coating was analyzed by an electron probe micro analyzer (EPMA).
  • EPMA electron probe micro analyzer
  • the atomic ratio of Cr/Ti/N was 16.5/29.3/54.2, and the atomic ratio of Cr to Ti was 3.6/6.4.
  • a rolling contact fatigue test was conducted to evaluate the peeling of the coating in an actual engine test.
  • a load was repeatedly applied to a test piece 9 sliding on a rotating drum 10 to cause the peeling of the coating in a relatively short period of time.
  • the detachment of the coating depends on a friction coefficient, a load (maximum Hertz stress), and the repetition number of load application under the same lubrication conditions.
  • the test conditions were as follows:
  • the test results were evaluated by whether or not the coating was detached. As a result of the rolling contact fatigue test in Example 1, the coating was not detached.
  • Example 2-8 ion plating was conducted under the film-forming conditions shown in Table 1, which also shows the film-forming conditions in Example 1.
  • Example 2 a lower partial pressure of N 2 than in Example 1 was used.
  • Example 3 a ratio of chromium to titanium was changed by changing arc current applied to the metallic chromium cathode and the metallic titanium cathode, and larger bias voltage than in Example 1 was used.
  • Example 4 and 5 the number of rotation of the table was smaller than in Example 1 to change the thickness of a unit laminate.
  • Example 6 arc current applied to the metallic chromium cathode and the bias voltage were larger than in Example 4.
  • Example 7 the bias voltage was larger than in Examples 3 and 6.
  • Example 8 the bias voltage was smaller than in Example 3.
  • the coating was constituted by CrN-type chromium nitride and TiN-type titanium nitride, the chromium nitride exhibiting the maximum peak in a (200) plane of CrN, and the titanium nitride exhibiting the maximum peak in a (200) plane of TiN.
  • the crystallite size was 9-40.3 nm in CrN, and 12.4-51.4 nm in TiN, and a sum of the crystallite sizes of CrN and TiN was 30.5-91 nm.
  • the coating composition about 5 atomic % of excessive N was measured, with an atomic ratio of Cr to Ti in a range of 3.6/6.4 to 5.5/4.5.
  • the measurement results of thickness, hardness and residual compression stress, as well as the rolling contact fatigue test results are shown in Table 4.
  • the coatings were as thick as 25.2-38.5 ⁇ m. With this value of thickness, the thickness of a unit laminate was calculated as 33-140 nm from the number of rotation of the table and the film-forming time. A ratio of the thickness of a unit laminate to a sum of the crystallite sizes of CrN and TiN determined by the X-ray diffraction measurement, which is shown in Table 2, was 1.08-1.54.
  • the coatings had hardness Hv of 1074-1553, and residual stress of ⁇ 505 MPa to ⁇ 2024 MPa (“ ⁇ ” means compression).
  • ⁇ means compression
  • Comparative Examples 1 and 2 commercially available piston rings having a CrN coating and a TiN coating, respectively, in place of the CrN/TiN laminate coating were measured with respect to thickness, hardness, residual stress, and X-ray diffraction, and subjected to a rolling contact fatigue test. The results are shown in Table 5. Comparative Example 1 had a coating having excellent chipping resistance with relatively high porosity and as low hardness Hv as 950, and Comparative Example 2 had a coating having relatively high hardness. Both coatings were detached under severe conditions in the rolling contact fatigue test.
  • Ion plating was conducted in the same manner as in Example 1, except for changing the arc-ion-plating cathodes to the same metallic chromium cathode as in Example 1 and a 99.7-%-pure metallic zirconium cathode (Example 9), and to the same metallic chromium cathode as in Example 1 and a titanium-aluminum alloy (50 atomic % Ti-50 atomic % Al alloy) cathode (Example 10), thereby forming a CrN/ZrN laminate coating in Example 9 and a CrN/TiAlN laminate coating in Example 10 on piston rings.
  • the arc current was 120 A at the metallic chromium cathode, 170 A at the metallic zirconium cathode, and 170 A at the titanium-aluminum cathode.
  • Example 11 CrN/AlN laminate coating
  • Example 12 TiN/AlN laminate coating on piston rings
  • the cathodes used in Example 11 were the same metallic chromium cathode as in Example 2, and a 99.9-%-pure metallic aluminum cathode.
  • the cathodes used in Example 12 are the same metallic titanium cathode as in Example 2, and a 99.9-%-pure metallic aluminum cathode.
  • the arc current was 200 A at the metallic chromium cathode, 200 A at the metallic titanium cathode, and 105 A at the metallic aluminum cathode.
  • the X-ray diffraction measurement results in Examples 9-12 are shown in Table 6.
  • the coatings were constituted by a CrN phase and a ZrN phase, a CrN phase and a TiAlN phase, a CrN phase and an AlN phase, and a TiN phase and an AlN phase, respectively.
  • the maximum peaks were obtained in a (200) plane of ZrN, a (200) plane of TiAlN, a (200) plane of CrN, and a (200) plane of TiN.
  • the crystallite size was 10.1-24.8 nm, and a sum of the crystallite sizes was 28.4-44.9 nm.
  • the measurement results of thickness, hardness and residual compression stress, as well as the rolling contact fatigue test results are shown in Table 7.
  • the coatings were as thick as 28.5-35.5 ⁇ m. With this value of thickness, the thickness of a unit laminate was calculated as 35.6-48.0 nm from the number of rotation of the table and the film-forming time. A ratio of the thickness of a unit laminate to a sum of the crystallite sizes determined by the X-ray diffraction measurement, which is shown in Table 6, was 1.04-1.29.
  • the coatings had hardness Hv of 1159-1394, and residual stress of ⁇ 576 MPa to ⁇ 977 MPa. In the rolling fatigue test, the coatings did not suffer detachment and surface cracking.
  • the piston ring having a hard laminate coating for excellent scuffing resistance, wear resistance and peeling resistance according to the present invention is provided with laminated compound layers having high thermal conductivity, it exhibits higher thermal conductivity necessary for piston rings than those of conventional hard CrN-coated piston rings.
  • High thermal conductivity contributes to permitting heat to efficiently escape from a piston head to a cooled cylinder wall, resulting in decreased thermal stress, thereby suppressing cracking and chipping.
  • the laminate coating comprising compound layers having relatively low Young's modulus, which act as stress-relaxing layers, suppresses the generation and/or propagation of cracks, thereby exhibiting high peeling resistance.
  • the laminated compound layers are provided with high crystallinity (high rigidity), thereby exhibiting high resistance to propagation of cracking.
  • higher crystallinity provides higher thermal conductivity.
  • the piston ring having a hard coating obtained by laminating layers made of different compounds has a well-balanced residual compression stress, thereby exhibiting excellent scuffing resistance, wear resistance and peeling resistance, so that it can be used in various severe environments.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Ceramic Engineering (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Physical Vapour Deposition (AREA)
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Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012200378A1 (de) * 2012-01-12 2013-07-18 Federal-Mogul Burscheid Gmbh Kolbenring
JP5965378B2 (ja) * 2013-10-31 2016-08-03 株式会社リケン ピストンリング及びその製造方法
BR102014025243B1 (pt) * 2014-10-09 2022-09-27 Mahle Metal Leve S/A Anel de pistão para motores de combustão interna, processo para obtenção de anel de pistão e motor de combustão interna
BR102015008817B1 (pt) * 2015-04-17 2022-08-30 Mahle International Gmbh Anel de pistão para motores de combustão interna
JP6343266B2 (ja) * 2015-09-09 2018-06-13 株式会社リケン 摺動部材及びピストンリング
US10030773B2 (en) 2016-03-04 2018-07-24 Mahle International Gmbh Piston ring
US10036472B2 (en) * 2016-03-04 2018-07-31 Kabushiki Kaisha Riken Sliding member and piston ring
JP6417438B2 (ja) * 2017-03-22 2018-11-07 株式会社リケン 複合クロムめっき皮膜、及び当該皮膜を有するピストンリング
US11162586B2 (en) 2017-06-02 2021-11-02 Mahle International Gmbh Piston ring and method of manufacture
US11047478B2 (en) * 2017-06-02 2021-06-29 Mahle International Gmbh Piston ring and method of manufacture
KR102064172B1 (ko) * 2017-09-01 2020-01-09 한국야금 주식회사 내마모성과 인성이 우수한 경질피막
CN107604312B (zh) * 2017-09-21 2019-11-19 湘潭大学 一种表面为(Ti,Al)N多层隔热耐磨超厚涂层的活塞及其制备方法和应用
CN110117774A (zh) * 2019-06-17 2019-08-13 广东工业大学 一种tc4钛合金表面涂层及其制备方法和tc4钛合金产品
CN110923639B (zh) * 2019-12-30 2021-08-27 岭南师范学院 附着在活塞环表面的MoTiCrWN复合涂层、活塞环及其制备方法
JP7402790B2 (ja) * 2020-12-17 2023-12-21 株式会社リケン 皮膜及びピストンリング

Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62188857A (ja) * 1986-02-13 1987-08-18 Riken Corp ピストンリング
JPH08312779A (ja) 1995-05-16 1996-11-26 Riken Corp 摺動材料およびピストンリング
JPH11335813A (ja) 1998-05-21 1999-12-07 Sumitomo Electric Ind Ltd 硬質被膜及び積層硬質被膜
JP2000274531A (ja) 1999-03-23 2000-10-03 Teikoku Piston Ring Co Ltd 摺動部材
US6325385B1 (en) * 1998-10-15 2001-12-04 Teikoku Piston Ring Co., Ltd. Piston ring
JP2002003976A (ja) 2000-06-15 2002-01-09 Teikoku Piston Ring Co Ltd 摺動部材
US20040067384A1 (en) * 2001-06-01 2004-04-08 Michael Hotger Sliding pairing for machine parts that are subjected to the action of highly pressureized and high-temperature steam, preferably for piston-cylinder assemblies of steam engines
JP2005060810A (ja) 2003-08-20 2005-03-10 Riken Corp 被覆材及びその製造方法
JP2005082822A (ja) 2003-09-05 2005-03-31 Ion Engineering Research Institute Corp 硬質厚膜被膜およびその形成方法
JP2005187859A (ja) 2003-12-25 2005-07-14 Ion Engineering Research Institute Corp 硬質厚膜被膜およびその形成方法
US20050218603A1 (en) * 2002-02-20 2005-10-06 Manfred Fischer Piston ring comprising a pvd coating
JP2007132423A (ja) 2005-11-10 2007-05-31 Riken Corp ピストンリング
JP2007278314A (ja) 2006-04-03 2007-10-25 Riken Corp 積層皮膜を有するピストンリング
US20080070815A1 (en) * 2006-09-19 2008-03-20 Nissan Motor Co., Ltd. Low friction sliding mechanism
US20100171272A1 (en) 2007-06-13 2010-07-08 Steffen Hoppe Piston ring
US20130168906A1 (en) * 2010-03-09 2013-07-04 Federal-Mogul Burscheid Gmbh Helical Compression Spring for an Oil Scraper Ring of a Piston in an Internal Combustion Engine and Method for Coating a Helical Compression Spring
US20140137733A1 (en) * 2011-06-24 2014-05-22 Kabushiki Kaisha Riken Piston ring

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2733013Y (zh) * 2004-09-24 2005-10-12 清华大学 多元多层纳米膜活塞环
JP5036232B2 (ja) * 2006-07-06 2012-09-26 Ｔｐｒ株式会社 内燃機関用ピストンリング
DE102006046917C5 (de) * 2006-10-04 2014-03-20 Federal-Mogul Burscheid Gmbh Kolbenring für Verbrennungskraftmaschinen
CN201180590Y (zh) * 2008-01-16 2009-01-14 中外合资安庆帝伯格茨活塞环有限公司 一种高耐磨活塞环

Patent Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62188857A (ja) * 1986-02-13 1987-08-18 Riken Corp ピストンリング
JPH08312779A (ja) 1995-05-16 1996-11-26 Riken Corp 摺動材料およびピストンリング
JPH11335813A (ja) 1998-05-21 1999-12-07 Sumitomo Electric Ind Ltd 硬質被膜及び積層硬質被膜
US6325385B1 (en) * 1998-10-15 2001-12-04 Teikoku Piston Ring Co., Ltd. Piston ring
JP2000274531A (ja) 1999-03-23 2000-10-03 Teikoku Piston Ring Co Ltd 摺動部材
JP2002003976A (ja) 2000-06-15 2002-01-09 Teikoku Piston Ring Co Ltd 摺動部材
US20040067384A1 (en) * 2001-06-01 2004-04-08 Michael Hotger Sliding pairing for machine parts that are subjected to the action of highly pressureized and high-temperature steam, preferably for piston-cylinder assemblies of steam engines
US20050218603A1 (en) * 2002-02-20 2005-10-06 Manfred Fischer Piston ring comprising a pvd coating
JP2005060810A (ja) 2003-08-20 2005-03-10 Riken Corp 被覆材及びその製造方法
JP2005082822A (ja) 2003-09-05 2005-03-31 Ion Engineering Research Institute Corp 硬質厚膜被膜およびその形成方法
JP2005187859A (ja) 2003-12-25 2005-07-14 Ion Engineering Research Institute Corp 硬質厚膜被膜およびその形成方法
JP2007132423A (ja) 2005-11-10 2007-05-31 Riken Corp ピストンリング
JP2007278314A (ja) 2006-04-03 2007-10-25 Riken Corp 積層皮膜を有するピストンリング
US20080070815A1 (en) * 2006-09-19 2008-03-20 Nissan Motor Co., Ltd. Low friction sliding mechanism
US20100171272A1 (en) 2007-06-13 2010-07-08 Steffen Hoppe Piston ring
JP2010529389A (ja) 2007-06-13 2010-08-26 フェデラル−モーグル ブルシェイド ゲーエムベーハー ピストンリング
US8273469B2 (en) 2007-06-13 2012-09-25 Federal-Mogul Burscheid Gmbh Piston ring
US20130168906A1 (en) * 2010-03-09 2013-07-04 Federal-Mogul Burscheid Gmbh Helical Compression Spring for an Oil Scraper Ring of a Piston in an Internal Combustion Engine and Method for Coating a Helical Compression Spring
US20140137733A1 (en) * 2011-06-24 2014-05-22 Kabushiki Kaisha Riken Piston ring

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
Ichimura et al., "Hardness and Adhesion of Arc-Ion Plated Nitride Films", Surface Technology, 2001, vol. 52, No. 1, pp. 110-115.
International Search Report, issued in PCT/JP2013/082830, dated Jan. 14, 2014.
Oki, "Surface Hardening by Dry Process and Its Trend", Surface Technology, 1990, vol. 41, No. 5, pp. 462-470.
Written Opinion of the International Searching Authority, issued in PCT/JP2013/082830, dated Jan. 14, 2014.

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WO2014088096A1 (fr) 2014-06-12
EP2930403A4 (fr) 2016-08-10
CN104838182B (zh) 2017-08-11
CN104838182A (zh) 2015-08-12
JP6325455B2 (ja) 2018-05-16
JPWO2014088096A1 (ja) 2017-01-05
EP2930403A1 (fr) 2015-10-14
US20150308573A1 (en) 2015-10-29

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